In the Quick Filter the list of file types can be accessed via the cursor keys.
In Win 10 it looks like this:
In Win 7 the highlighter is missing:
It's just a cosmetic bug, (de-)selecting a file type with the space key still works.
Thanks, we'll get that fixed. (Update: Has been fixed for 12.8.2.)
It's not Windows 7 but having visual styles disabled (which is a lot harder to do in Windows 10). Win 7 is OK with visual styles left enabled:
